The girl that is the easy, last resort fuck at the bar or party. You go around the party trying to hook up with some real hot chicks that you haven't had sex with yet and if you can't get them to come back to your place tonight you always have the settler to fall back on because you know she is always down to get slammed.

Jon: Amanda is the settler tonight. She's such a slampig.
Ed: What's a settler?
Jon: Well if you can't bring any other slut back you gotta settle for her.

Within a successful, seemingly stable relationship, the settler refers to the "better half", who in essence settles with their partner. This person tends to be either more attractive, wealthier, smarter, personable or some other quality that would seemingly make their partner look inferior, to the extent that people begin to question why they would even date in the first place.

Name given to someone when they are addicted to the computer game Settlers. The person carries a laptop around campus - ready to play at any time. The person may ask you to play with them at random and often awkward times. This character may form a nightly gang of Settlers who enjoy playing the game for hours at a time.